Electrical apparatus



Jan. 12, 1937. c. w. METCALF ET AL ELEGTRI CAL APPARATUS Filed Nov. 20, 1954 INVENTOR BY. Ma? :8 W44 fiom y Patented Jan. 12, 1937 UNITED STATES PATENT OFFICE ELECTRICAL APPARATUS Clarence W. Metcalf, Haskins, Roslindale,

Sharon, and Rupert L. Mass., assignors to Tobe 8 Claims.

The present invention relates to a device to be used in connection with an electrical transmission line with a radio antenna or any electrical device where an adjustment of the electrical characteristics of the system need to be varied.

The present invention is applicable to transmission lines for loading these lines at various places, and it is also applicable to antenna construction where the antenna may be loaded to provide the desired electrical characteristics.

It is fairly common practice in the electrical art to provide adjustment of electrical inductances at various points in the system. In the telephone transmission lines it is common practice to connect in circuit at various points of the transmission line, so called loading coils, the purpose of which is to adjust the phases of the current and voltage upon the line so that transmission will be continued over the line in the same relation that it was first impressed upon the line.

Loading of antenna circuits, has been employed by connecting loading coils at points near the receiving set to which the lead-in from the antenna is connected. This method has a number of disadvantages in particular in the shorter waves where the length of any conducting element in itself distorts the phases of current and voltage and changes the tuning of the system.

In order to obtain the best results from load ing the antenna, the applicant in the present invention has constructed a device by which the antenna may be loaded in the antenna itself and may also serve as a structural element for not only insulating, but also supporting the antenna and furnishing as a whole, means of connecting the antenna to the ground or to the lead-in wire.

The device of the present invention has particular application in use in antennae of the shorter wave lengths, for instance antennae ranging in wave length from five to one hundred and fifty metres.

The invention also has particular application in connection with a so called doublet as applied to a form of antenna. A doublet is a double antenna which is symmetrical with a given plane and in which the one half furnishes the counter poise over the other half. In this form of antenna the unit described more particularly in the present invention is applied in the plane of symmetry of the antenna and furnishes a loading element at that point which may properly adjust the antenna characteristics both in wave length and damping at the point where the receiving or sending set is connected,

The device of the present invention may take various forms and it may be applied to antenna construction not only in connection with a single doublet but also with a double doublet so called in which two doublets are used in a substantial symmetrical arrangement one with the other.

Not only may the device be used in various forms of antenna but the construction of the device may be made in a number of ways some of which are indicated and described in the drawing annexed hereto, in which:-

Figure 1 shows the invention as applied to a single antenna.

Figure 2 shows a modification as applied to a double antenna or doublet.

Figure 3 shows a modification as applied to a double doublet.

Figure 4 shows the invention as applied to a stand-01f insulator, and

Figures 5a. to 5 show various modifications indicating various types of sections that may be used in the devices indicated in the other figure for providing proper connecting facilities between different sections of the elements.

In Figure 1, the core I may be made of porcelain or other similar material such as is commonly used in insulators. The body may also be provided with ribs 2, 2, 2, etc., as is the ordinary high tension insulator with depressions in between as indicated by 3, 3, 3, etc., at each end of the body there may be provided in the rounded heads 4, 4, holes 5 and 5.

The antenna connection or conductor 6 is threaded about the end heads 4 through the hole 5 and wound about each depression 3 as indicated clearly in Figure 1.

As indicated more clearly in Figure 1, a groove or cut I may be provided in each rib or collar 2 through which the antenna conductor 6 is threaded to the next depression. The antenna conductor 6 at one end may be connected directly to the antenna or to the ground or said lead. It the element is used at the end of the antenna the conductor 6 may be carried to another insulator the opposite end of which may be. used to support the antenna in place. This is not shown in Figure 1 as the application is obvious. The body may be wound with the desired number of turns, but usually for ordinary work three or four turns for each section is proper. The element may be used in series if sufiicient induction is not supplied by one alone.

In Figure 2 a modification of the device shown in Figure l is indicated. Here, the shoulders or ribs 9, 9, merge at the center into the neck 3 and provide thereby two sets of grooves l0, l9, ID, on the left of the neck 8, and H, II, II, to the right of the neck 8. The ends of the element are similar to that indicated in Figure 1 and are provided with holes l2 and I2 through which the conductors l3 and I4 may be threaded. Two holes l5 and I6 are provided in the neck 8 through which the other ends I! and [8 respectively of the conductors l3 and I4 may be threaded. Similarly as indicated in Figure 1, the conductor l3 may be connected to one flange of the doublet of the antenna and the conductor I I to the other flange of the doublet. Grooves l9, 19, I9, etc., may be provided in each shoulder 9 to allow the conductor to be threaded from one groove to the next groove. The inductance of the unit may be made of such a value as would be proper for particular types of antennae, or if necessary the device shown in the Figure 2 may be used in conjunction with that shown in Figure 1, in which case the end i3 of the conductor would be connected to the conductor [3, and the end M to a similar unit.

In the modification indicated in Figure 3, a so called unit for a so called double doublet is shown. This unit is constructed of the same material as the units indicated in Figures 1 and 2. The unit indicated in Figure 3 is similar to that shown in Figure 2, except that in the center neck 20 there is provided two sets of holes, 2|, 22 and 23, 24, and a further center hole 25. The conductor 26 is threaded through the hole '21 in the same manner as has been described above and is similarly wound about the grooves 28, 28, as has been previously described. Upon emerging from the groove nearest the center, a wire 25 is threaded through the hole 21 and carried diagonally across to the hole 24 through which it is again threaded. Similarly the wire 21 is threaded about the groove 28 at the right of the element through the hole 23 diagonally across and through the hole 22 from which it emerges as indicated. A tap or electrical connection 28 is made to the wire 26 threading through the hole 2| and a similar electrical connection is made with the tap 29 threading through the hole 23. Both of these connections are tied together but may be insulated from each other as shown at 30 and carried through the hole 25 emerging in the separate leads 3| and 32. This indicates an arrangement that may be used for a so called double doublet. In this case the conductors 3i and 32 provide the lead in element for the antenna circuit, the doublet on one half being connected to the left end of the wire 26 and on the: other half being connected to the right end of the wire 26. The second doublet in this double doublet connection is connected at the right end to the wire 21 emerging from that end of the. element and at the left end to the wire 21 emerging from the hole 22. This connector may also be used in conjunction with the element shown in Figure 1 in the manner that has been indicated above.

In Figure 4 is shown how the device may be applied to an element to be attached to a solid base, such as is in a way similar to that in which a stand-off insulator is used. Here a base 32 may be provided in which there are holes 33 and 34 for fastening the element to a solid base. A wire 35 may be wound about the grooves 36 in the same manner as has already been indicated in connection with the other figures. The leadin connection in this case may be either at the end 31' or at the end 35, whichever might be more advantageous.

While the elements shown in Figures 1, 2, 3, and 4 indicate straight out sections, as indicated at 38 in Figure 5a, other types of slots between sections where the winding is made may be used.

Figure 519 at 39 shows a slanting section at 39.

Figure 5c shows merely a projection 40 from the body itself.

Figure 5d shows a pin 4| which may be inserted in the element.

Figure 56 shows a hole 42, and in Figure 5f, the plane element may be used without any groove in which case the wire screws for the shoulder are shown at 43.

It is also possible to construct the device shown in Figures 1, 2, and 3 as helical elements in which no groove is necessary between sections, but in this case only one turn can be applied without in some way making provision for returning the wire back to the beginning again.

Not only may a single helical spiral be used, but double and treble spirals, in which case the inductance may be increased when more turns are used.

Having now described our claim:-

1. An article of manufacture comprising a body of insulating material having sections made of grooves by ribs carried up at the sides thereof, the ends of said body merging into a rounded cap having a hole therethrough and electrical conducting means wound in said grooves and threaded into the holes in the end caps.

2. An article of manufacture comprising a body of insulating material having a centre collar section having two holes therein, and symmetrical end sections formed of a plurality of ribs forming grooves therebetween, slots in said ribs communicating with successive grooves, a cap formed invention, we

in the body at the ends thereof having holes therein and two independent conductors one wound over the right and left grooves respectively and threaded into said holes.

3. An. article of manufacture comprising a body of insulating material having a center collar section having two sets of holes therein, and symmetrical end sections formed of a plurality of ribs forming grooves therebetween, slots in said ribs communicating with successive grooves, a cap formed in the body at the ends thereof having holes therein, the body being symmetrically constructed and two independent conductors wound in said groove, each threaded through an end hole and a hole at the center and a center tap taken at the collar section.

CLARENCE W. METCALF. RUPERT L. HASKINS. 

